Gaseous electric discharge lamp



Feb. 11, 1936. V, k. WIEGAND 0 2,030,805

GASEOUS ELECTRIC DISCHARGE LAMP Filed MarCh 25, 1935 INVENTOR ATTORNEY Patented Feb. 11, 1936 UNITED" STATES GASEOUS ELECTRIC nrsormnoamm Kurt Wiegand, Berlin-Neu-Tempelhot, Germany,

assignor to General Electric Company, a corporation of New York ApplicationMarch 25, 1935, Serial No. 12,925 In Germany March 28, 1934 3 Claims.

The present invention relates to gaseous electric discharge lamps generally and more particularly the invention relates to such lamps having a luminescent material associated therewith to complement or supplement the light emitted by the luminous gaseous electric discharge therein.

When such lamps have a body of phosphorescent material associated therewith it is possible to operate the discharge intermittently at a tre quency such that duringthe periods when the discharge is non-luminous the phosphorescent materialgives off light and the lamp emits light continually in spite of the intermittent operation of the luminous discharge. This improves the efliciency of such a lamp, that is, the quantity of light emitted per unit of energy consumed is greater. when a time switch is connected into the lamp circuit to eflect the intermittent operation of the luminous discharge the increased 'efliciency of the lamp itself is partially or wholly oiT-set by the energy consumed in operating the time switch so that the overall efliciency of the lamp outfit is little or no greater than itwould be if the luminous discharge were operated continuously and the phosphorescent material were omitted. The time switch also increases the cost of the outfit and is not a very reliable discharge regulator, particularly over a long life. r

v The object of the present invention is to pro-r vide an apparatus comprisinga gaseous electric discharge lamp having phosphorescent material associated therewith which is an eflicient, reliable light source. Another object of the in vention is to provide an inexpensive apparatus of this type. Still further objects and advantages attaching to the device and to its use and operation. will be apparent to those skilled in the art from the following particular description. I

In accordance with these objects the new and novel lamp outfit comprises'a gaseous electric discharge lamp having phosphorescent material in or on the walls of the container thereof and having electrodes sealed therein. At least one of said electrodes a thermionic electrode and at least another of said electrodesis a cold, sheet metal electrode. The lamp is connected across the terminals of an alternating current source, such as a transformer. The lamp thusjoperates on the rectifier principle and the discharge incident at the cold electrode operates and is luminous only during one-half of each cycle 01' said alternating current source. During the other half-cycle, when the luminous discharge is not operating, the light emitted by the lamp comes from the phosphorescent material. The lamp thus appears to be continually luminous.

In one embodiment of the invention a therm- 5 ionic electrode mounted'at one end of an elongated, tubular lamp container and a cold electrode is mounted at the other end thereof. The lamp is connected across the terminals of an alternating current source and the operation 0 thereof is as described above. In another embodiment of the invention a thermionic electrode is mounted in the center of a similar container and a cold electrode is mounted at each end of the container. In still another embodiment of the invention a cold electrode is mounted in the center of a similar container and a thermionic electrode is mounted at each end of the container. In these last two embodiments the electrodes are connected to the terminals of the current source in such manner (described later herein) that a discharge takes place in each half of the lamp on each cycle of the alternating current source and on one half cycle a discharge takes place in one half of the lamp and on the other half v cycle the discharge takes place in the other half of the lamp. Each half of the tube then emits light from the luminous discharge therein during one half of each cycle and from'the phosphorescent material during the other half oi'each cycle. A discharge thus takes place in said lamp on each half cycle of-said alternating current source, even though said discharge extends over one half the length of said lamp. The discharge in one half 01' the lamp facilitates the restarting of the discharge in the other half or the lampon the next half-cycle. This particular operationof the lamp isalso favorable since the light from the discharge in one-half of the tube strongly excites the phosphorescent material inthe other half of the lamp which gives ofi a more intense light than it would otherwise which increases the efllciency of the lamp.

In the drawing accompanying and' forming part of this specification several embodiments of the invention are shownin which p I Fig. 1 illustrates an apparatus embodying the invention and isa side elevational view of a gaseous electric discharge lamp and a wiring diagram of a circuit thereof,

Fig. 2 illustrates another apparatus embodying the invention and is a similar view of another lamp and a wiring diagram of a circuit thereof.

Fig. 3 illustrates still another apparatus em bodying the invention and is a similar view of 5 as well as visible light rays.

another lamp embodying the invention and a wiring diagram of a circuit therefor, and

Fig. 4 illustrates still another apparatus embodying the invention and is a similar view of another lamp embodying the invention and a wiring diagram of a circuit therefor.

, Like numbers denote like parts in all the figures.

Referring to Fig. l of the drawing the new and novel lamp comprises an elongated tubular container I having a thermionic electrode 2 sealed into one end thereof and a cold, sheet metal electrode 3 sealed into the other end thereof. Said electrode 2 consists of rod of electron emittin g material, such as a rod of barium oxide, and a heating filament, such'as a tungsten filament, wrapped around said rod. Said container I has a starting, rare gas therein, such as argon, neon, or krypton, and a quantity 4 of vaporizable material, such as mercury, the vapor of which when excited by the passage of an electric discharge between said electrodes 2 and 3 emits ultra-violet Said container I has a layer or coating 5 of phosphorescent material, such as zincsulphide, calcium tungstate, magnesium molybdate, zinc-cadmium sulphide, cadmium tungstate, or zinc silicate, thereon. The

" phosphorescent material 5 is made light emitting by therays emitted by the discharge in the gaseous atmosphere and continues to emit light for a time after the discharge is extinguished.

Each of said electrodes 2 and 3 is connected by the leads 9 and II! respectively to a terminal of thesecondary coil 1 ofv the transformer 6, 'I. The primary coil 5 of said transformer is connected across the terminals of an alternating current source. A choke-coil 8 is connected to the primary side of said transformer 6, I. The electrode 2 is connected by the lead II and said lead 9 across several turns of. said transformer secondary Iv which furnishes the heater current for said electrode 2 When current is applied to the above described circuit a discharge takes place between the electrodes 2 and 3 in the container I. The discharge occurs onthat half cycle during which the thermionic electrode 2 is negative. During the other half cycle no discharge takes place between said electrodes 2 and 3. The lamp thus operates as arectifier. The rays emitted by the discharge excites the phosphorescent material 5 to a light emitting condition which condition persists after the discharge has been extinguished. Thus the lamp emits light during the half cycle when the dischargeis not operating as well as during the half cycle when the discharge is operating.

The embodiment of the invention illustrated in Fig. 2 of the drawing is thesame as that illustrated in Fig. 1-except that in this embodiment the thermionic electrode 2f is mounted. in the middle of the container I and a cold, sheet metal electrode 3' is mounted at each end of the container I. Each of said electrodes 3' is connected by leads I2 and. I3 to'the ends of the secondary I. The thermionic electrode 2' is connected across several turns of wire on either side of the midpointof said secondary I bycurrent leads I 4 and I5. In this embodiment two chokecoils I6 and v I"! are connected into the leads I2 and I3 respecof the alternating current sourceand'the electrodes 3' are positive alternately, one on each half-cycle. A discharge thus takes place in said container I on each half-cycle of said current source; during one-half cycle the discharge takes place in one half of the container I and during the other half-cycle in the other half of said container I. The period during which no discharge takes place in one half of the lamp is not noticeable to the eye since the phosphorescent material emits light during this period as in the embodiment of Fig. 1. phosphorescent material emits a more intense light during this period, since the rays from the discharge in the other half of the lamp excite the material, and the discharge in this half of the tube starts earlier in the cycle and therefore persists longer during the half-cycle since the starting thereof is facilitated by the discharge in the other half of the lamp. This embodiment of the invention therefore is even more eflicient than the embodiment illustrated in Fig. 1.

The embodiment of the invention illustrated in Fig. 3 of the drawing is similar to that shown in Fig. 2 except thatin this embodiment the electrodes 3' are connected to the same terminal of said secondary by said leads I2 and I3 and thermionic electrode 2' is connected to the other terminal of said secondary 1 by'lead I8. In this embodimentthe electrode 2 consists of a fllament wrapped around a bar of electron emitting material and is heated to its electron emitting temperature by the, discharge incident thereat. The operation of this'embodiment of the invention, however, is the same as illustrated in Fig. 1, that is, a discharge takes place in each half of the container I on each half-cycle of said However, in this embodiment the current source and no discharge takes place in. said lamp on theother half-cycle.

The embodiment of the invention illustrated in Fig. 4 is the same as that illustrated inFig. 3 except that in this embodiment a cold electrode 3", such as a metal, a metal carbide, or graphite electrode, is mounted in the middle .of the container I and a thermionic electrode 2", similar to the electrode 2 of Fig. 3 is mounted at each end of said container I. As in the embodiment of Fig. '3 the end electrodes 2" are connected to one terminal of the transformer secondary l byleads I2 and I 3 having choker coils I6 and I1 connected therein respectively and the middle electrode 3" is connected to the other terminal of said transformer secondary! by lead I8. The operation of this embodiment is the same as that of the embodiment shown in Fig. 3, that is, a discharge takes place in both halves of said container I on the same halfcycle of the alternating current sourceand no discharge takes place in said container I onthe other half-cycle.

While I have shown and described and have pointed out in the annexed claims certain novel features of the invention, it will be understood that various omissions, substitutions and changes in the forms and details of the device illustrated and in its use and operation may be made by those skilled in the art without departing from the broad spirit and, scope of the invention, for example, the container I is made of a phosphorescent glass, when desired, in which case the layer of phosphorescent material is omitted when desired, the layer of phosphorescent material is applied to the outer wall of said containerul, or is incorporated in the walls thereof in which case the container I is made of an ultraviolet transmitting material. Other types of thermionic electrodes are used in place oi those shown and described, such as the Hull electrode or the Pirani electrode, when desired.

What I claim as new and desire to secure by Letters Patent 0! the United States is:-

11 A lamp unit comprising in combination a gaseous electric discharge lamp comprising a container, electrodes sealed therein, a gaseous atmosphere therein and a phosphorescent material associated with said container, two of said electrodes being cold electrodes, another of said electrodes being a thermionic electrode, said cold electrodes being mounted on opposite sides of and at equal distances from said thermionic electrode, the rays emitted by said gaseous atmosphere, when excited bythe passage of a discharge between said electrodes, causing said phosphorescent material to emit light and an alternating current source for said lamp, said current source being a transformer, said thermionic electrode being connected to the mid-point of said transformer and said cold electrodes being connected to opposite ends of said transformer.

2. A lamp unit comprising in combination a gaseous electric discharge lamp comprising a container, electrodes sealed' therein, a gaseous atmosphere therein and a phosphorescent material associated with said container, two oi said electrodes being cold electrodes, another 0! said electrodu being a thermionic electrode, said cold electrodes being mounted on opposite sides of and at equal distances from said thermionic electrode, the rays emitted by said gaseous atmosphere, when excited by the passage of a discharge between i said electrodes, causing said phosphorescent material to emit light and an alternating current source for said lamp, said thermionic electrode being connected to one terminal of said current source and said cold electrodes being connected to the other terminal 0! said source.

3. A lamp unit comprising in combination a gaseous electric discharge lamp comprising a container, electrodes sealed therein, a gaseous atmosphere therein and a phosphorescent material associated with said container, two of said electrodes being thermionic electrodes, another of said electrodes being a cold electrode, said thermionic electrodes being mounted on opposite sides of and at equal distances from said cold electrode, the rays emitted by said gaseous atmosphere, when excited by the passage of a discharge between said electrodes, causing said phosphorescent material to emit light and an alternating current sourceior said lamp, said cold electrode being connected to one terminal 0! said current source and said thermionic electrodes being connected to the other terminal or said source.

KURT WIEGAND. 

